The present invention relates to lifting and leveling (i.e., repairing) existing buildings that have settled unevenly or, for some other reason, have become unstable and need to be re-leveled and stabilized. More particularly, the present invention relates to a method and apparatus for repairing existing buildings by utilizing a support system that comprises an apparatus having non-cylindrical support sections that are driven into the earth underneath the building foundation. The non-cylindrical support sections are strong and have relatively low bearing characteristics and relatively high friction characteristics.
Several methods and systems have been developed and used for lifting, leveling and stabilizing existing buildings. One common technique used for re-leveling and stabilizing buildings and houses is accomplished by digging a hole underneath a building foundation to a depth generally equal to the length of a cylindrical cement support piling (e.g., 12 inches), driving the cylindrical cement support pilings into the ground one on top of the other until a particular depth has been reached, and jacking a portion of the building up to a particular height by utilizing a jack that is located on the top surface of the uppermost piling.
The pilings are typically driven into the ground until a rock strata is encountered or until the depth of the hole containing the pilings is believed to be sufficiently deep. In situations where a rock strata cannot be reached, the pilings are typically driven to a depth great enough to cause friction between the earth and the outer surfaces of the pilings to prevent substantial movement of the pilings.
One of the problems associated with using this approach is that the cement pilings must have relatively large diameters to provide them with sufficient strength to be driven into the ground to a particular depth and to support the building. The larger the diameter of the cement piling, the more bearing it has, which makes it more difficult to drive the piling into the ground. Another problem associated with using cement pilings is that they often shatter when rock strata and/or tree roots are encountered. For all of these reasons, this type of support system is undesirable.
Another common technique for re-leveling and stabilizing buildings utilizes steel cylindrical pipe sections that are driven into the earth adjacent the side of the building until a sufficient depth is reached. The building foundation is then jacked up using a hydraulic jack to a desired height, and then the foundation is bracketed to the uppermost steel pipe section. The jack is then removed and the building is supported and stabilized by the support system. One of the benefits of using hollow steel pipe sections for this purpose is that they have less bearing than the aforementioned concrete pilings due to the fact that the steel pipe support sections are smaller in diameter than the concrete pilings. Also, steel pipe used for this purpose is normally stronger than concrete and therefore is unlikely to break when rock or tree roots are encountered. However, the steel pipe support sections may bend, which results in instability in the support structure.
One of the disadvantages of using hollow steel pipes for this purpose is that the smaller diameter results in overall less friction between the earth and the surfaces of the steel pipe sections. Also, steel pipes, even if they are galvanized, tend to rust due to water collecting within the pipes after the system has been installed. Furthermore, bracketing the steel-pipe support system to the side of the building foundation tends to exert undesirable pressure on the outside of the building, which can result in structural damage to the building.
Accordingly, it would be desirable to provide a method and an apparatus for lifting and leveling existing buildings that overcome the aforementioned problems associated with existing support systems. The present invention provides a method and an apparatus for lifting and leveling existing buildings by utilizing a support system that lifts and levels an existing building from underneath the building utilizing non-cylindrical support sections. The apparatus of the present invention comprises at least one non-cylindrical support section that is substantially rectangular in shape and has first and second ends. The non-cylindrical support section is, in accordance with the method of the present invention, driven into the earth at a position underneath the existing building such that the first end of the first non-cylindrical support section is located beneath the second end of the first non-cylindrical support section. A cap support section is then placed in contact with the second end of the first non-cylindrical support section. A jack is disposed on the upper side of the cap support section and raised until the foundation of the existing building has been lifted to a desired height.
The non-cylindrical support section has low bearing and high friction characteristics. The low bearing characteristics enable the apparatus to be driven further into the earth than cylindrical pilings that are commonly used to lift and level existing buildings. The high friction characteristics assist in maintaining the stability of the apparatus once it has been installed.
These and other features and advantages of the present invention will become apparent from the following description drawings and claims.